1. Field of the Invention
The present invention relates to systems and methods for protecting vehicle occupants from injury. More specifically, the present invention relates to covers that permit multi-axis deployment of inflatable cushions.
2. Description of Related Art
The inclusion of inflatable safety restraint devices, or airbags, is now a legal requirement for many new vehicles. Airbags are typically installed in the steering wheel and in the dashboard on the passenger side of a car. Additionally, airbags may be installed to inflate beside the passenger to provide side impact protection, in front of the knees to protect the knees from impact, or at other strategic locations.
In the event of an accident, an accelerometer within the vehicle measures the abnormal deceleration and triggers the ignition of an explosive charge. Expanding gases from the charge fill the airbags, which immediately inflate to protect the driver and/or passengers from impact against the interior surfaces of the vehicle. During normal vehicle operation, airbags are typically stowed behind covers to protect them from tampering and provide a more attractive interior facade for the vehicle.
Unfortunately, vehicle occupants may move considerably from optimal impact positions. For example, a passenger may be adjusting the radio or air conditioning settings, tending to a child in the rear seat, reclining in the seat, or otherwise moving in a manner that positions part of their body outside the protection zone for a typical prior art airbag. Hence, when impact occurs, a part of the person's body may strike the vehicle interior outside the perimeter of the airbag, or the person may even be injured in some manner by the inflating airbag.
This problem is caused, at least in part, by the fact that many known airbags inflate only in a single direction, which is often toward the person. For example, front impact airbags typically inflate primarily in a rearward direction, directly toward the driver or passenger. Hence, interior surfaces of the vehicle that surround the stowed position of the cushion may not be sufficiently covered by the cushion by the time the person's body moves toward them. Thus, such surfaces are exposed to receive impact with parts of the person's body that are not aligned with the inflating cushion.
Furthermore, the momentum of the deploying cushion can also be a source of injury to vehicle occupants. When the majority of the gas produced is directed toward the occupant, the mass of the gas will create significant momentum in the deploying cushion. The momentum of the bag toward the person has an additive effect on the momentum of the person toward the bag, thus making the impact more dramatic.
The deployment of known cushions is often determined, at least in part, by the configuration of the covers that contain them. Many known covers have seams arranged to permit emergence of the cushion in essentially a single direction. Lateral or transverse deployment of the cushion is restricted by walls of the cover.
Accordingly, a need exists for airbag covers that permit deployment of a compacted cushion along multiple directions. Such covers are needed for a wide variety of airbag types, including driver's side airbags, passenger's side airbags, side impact airbags or “inflatable curtains,” and knee bolsters. Multi-axis deployment should preferably occur in normal operation of the cover, and not simply in the event that deployment toward the person is obstructed. Furthermore, such a cover should preferably be easily manufactured and installed in a vehicle.